PreventDefault on Blazor input

Question

I have a simple application with an input field that should insert a predefined piece of text as you type.

The code I have looks like this:

Answer 1

Ok, this is a bit dirty tricky: remove the last char to override user input key:

// ...
private int _petitionCharStep = 0;
private string _petition = "This is a dummy text";
public string PetitionInput { get; set; } = string.Empty;

void PetitionHandleKeyDown(UIKeyboardEventArgs arg) {
    if (_petitionCharStep >= _petition.Length  )
    {
        PetitionInput = _petition.Substring(0, _petition.Length-1 );
        _petitionCharStep--;
    }
}

void PetitionHandleKeyUp(UIKeyboardEventArgs arg) {
    if (_petitionCharStep < _petition.Length  )
    {
        PetitionInput += _petition[_petitionCharStep];
        _petitionCharStep++;
    }        
}

Test it at blazorfiddle.